Mechanical-stoker regulator



c. e. KING ET! AL MECHANICAL STOKER REGULATOR Filed Jan. 12. 1923 Patented Dec. 15, 1925.

UNITED STATES 1,566,102 PATENT OFFICE.

CLAUDE G. KING AND EARL TUBBS, OF CEDAR RAPIDS, IOWA.

MECHANICAL-STOKER REGULATOR.

Application filed January 12, 1923. Serial No. 612,196.

To all whom it may concern:

Be it known that we, CLAUDE G. KING and EARL Teens, citizens of the United States, residing at Cedar Rapids, in the county of Linn and State of Iowa, have invented certain new and useful Improvements in Mechanical-Stoker Regulators; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and use the same.

This invention relates to stokers such as are in common use in steam-generating plants, the fuel being carried rearward in a thin layer on an endless chain grate.

The object of this invention is to automatically regulate the travel of the grate according to steaming demands, the move ment of the grate being arrested when the production of steam exceeds normal requirements, and through mechanism controlled by the production or flow of steam itself.

The nature of the invention will fully appear from the description and claims following, reference being had to the accompanying drawing, in which i Fig. 1 is a fragmentary side elevation, partly in section, illustrating a common type of steam generating furnace, equipped with a stoker of theendless chain-grate type, and showing also a sideelevation of our improved regulator as applied thereto. Fig. 2 shows in enlarged detail the forward feed mechanism for the grate. Fig. 3 is a plan view'of' the same. Fig. 4] is a fragmentary View illustrating in detail and conventionally means for efl'ectmg the grate control through the operation of a steam flow meter by the use of electrical devices.

Before describing the regulating apparatus it is to be understood that as adjusted for service the grate is supposed to afford an excess of combustion for normal demands. It is of course common to modify this combustion by means of dampers, and the like, but our invention contemplates arresting or stopping the rearward movement of the grate itself, so that the supply of fresh fuel for combustion is arrested or cut off, until more is demanded. The saving of fuel is thus made absolute, instead of its depending uncertainly upon a varying supply of oxygen to regulate combustion in a mass of fuel fully exposed thereto. Our method insures complete, and it may be, rapid and eifectivecombustion, the line of complete combustion advancing toward the front from the rear end of the grate when the movement of the grate is arrested, whereas if the grate moves regularly and continuously rearward, economic regulation of combustion, in a thin layer of fuel, by changing the air supply, is difficult and uncertain.

- Referring now to Fig. 1, the numeral 5 denotes a chain-grate mounted on sprockets 6 at the front and rear, the front one not being shown, but indicated by its axle 7. The grate is made to move slowly backward, as indicated by the arrow, by means of a ratchet 8, and a train of reducing gears 9, which need not be described. The ratchet is given a step-by-step movement by an oscillating arm 10 carrying a pawl 11. The depending connecting-rod 12 is supposed to connect with a continuously rotating eccentric, not shown. The forward impulse of the ratchet is held by a detent pawl 13, otherwise weight and slack of the grate would cause back-lash of the ratchet, and the grate would advance irregularly, or not at all. Our invention takes advantage of-this fact, and by controlling the position of the detent pawl we are able to regulate the movementof the grate easily and accurately.

A flow-meter 14, of a familiar type, is provided with a tracing or pen arm 15, which records fluctuations and the general course of steam-flow according to its position with respect to the record sheet 16. By means of a cam 17 suitably connecting with this arm, an electric circuit is closed at 18 when the arm reaches a predeterminedswing to the left. This may be at any desired point, the cam being adjusted on the arbor of the swinging arm by a screw 1".

Over the ratchet is mounted on a standard 19 a lever 20, one end of which connects by a link 21with the detent pawl. The other end of the lever connects with the core of a solenoid 22. The coil of the solenoid is in circuit with the switch 18. An excess of swing of the tracing arm to the left closes the circuit, and the pull of the solenoid lifts the detent pawl out of engagement with the ratchet. If but one detent pawl is used the forward, that is to say, the advancing movement of the chain grate stops until by a. lessening of combustion the steam flow is diminished and the tracer swings back, opening the circuit. when normal action is resumed.

In practice it is found desirable to merely retard the advance of the grate, and not stop it entirely. Thisis effected by providing two detent pawls. One of these, 13 is slotted at 13, so as to slip halt a ratchettoot-h space on its supporting stud 23. Litting the other pawl in this case brings the slipping pawl into engagement with the ratchet, and the grate is driven at half speed, as will be evident.

In practice, also, it is found desirable to energize the solenoid through a relay 24:, as shown in Fig. 4, ins ead of directly, as shown in Fig. 1, conventionally, as is also the primary source of energy, and a switch tor independently closing and breaking the circuit.

The device has been found to give very accurate and steady control of the furnace with respectto steam-flow, with small deviations in the position of the tracer, and economy in the consumption of fuel.

Having thus described our invention, we claim:

1.. In combination with a chain-grate stoker tor a steam-generating furnace having a limited back-lash, means including a. ratchet and pawl and actuating mechanism, to advance the grate, a detent pawl to prevent back-lash, a steam-flow meter having a movable member, and means connecting the same operatively with the detent pawl to disengage it according to fluctuations in the steam flow.

2. In combination with an endless chaingrate for steam generating furnaces having a limited back-lash, means including a reciprocating pawl and a ratchet engaged thereby, to advance the grate, a plurallty 0t detent pawls, one having a slip motion to arrest a part of the grates back-lash, a movable steam-flow registering member connecting with the other detent pawl, and 0p erable by the fluctuation in steam flow to disengage the same,'whereby an excess of steaming automatically causes retarded n'iovement of the grate.

3. In combination with an endless chaingrate for steam-generating furnaces hav 'ing a limited back-lash, means including a ratchet and reciprocating pawl to advance the grate, a detent pawl to arrest back-lash, amovable steam-registering member, a link connecting with the detent pawl, and electrical means connecting with said link, and closable by said registering member.

at. In combination with an endless chaingrate for steam-generating furnaces having a limited back-lash, means including a ratchet and reciprocating pawl to advance the grate, a detent pawl to arrest back-lash, a connecting link, a lever, a connected solenoid, a connection of the other end of the lever with the detent link, steam-registering means having a movable member, and a switch forming part of an electric circuit ot' the solenoid actuated by fluctuations in said registering mechanism.

The combination with a chain-grate tor stean'i-generating furnaces having a limited back-lash, means including a ratchet and reciprocating pawl to advance the grate, a detent pawl to arrest its back-lash, a connecting link, a steam-flow meter having a movable member to register fluctuations in steaming, an electric switch actuated by the movement of said member, a solenoid in circuit therewith, a lever actuated by the solenoid, and a connection of said lever with said detent link.

(3. In combination with a chain-grate for steam-generating furnaces having a limited back-lash, means including a ratchet and pawl to advance the grate, a detent pawl to arrest back-lash thereof, a lever connecting with the detent pawl, a SOlGIlOlQ L150 in connection with said lever, a relay to energize said solenoid, a switch in the relay circuit, steam-registering means having a switch-actuating member movable according to steam fluctuations, and an adjustable cam co-operating with said movable member, and adapted to close said relay switch.

7. In combination with a chain-grate having a limited back-lash, means including a detent pawl to arrest back-lash oi the grate, a lever connecting with said detent pawl, a solenoid also connecting with the lever, a relay and its electric circuit adapted to energize the solenoid, a switch in the relay circuit, steam-registering means having a movable member to denote fluctuations in steaming, and a member connected therewith to close the relay switch in an excess steaming position.

In testimony whereof we afiixe our signatures.

CLAUDE G. KING. EARL TUBBS. 

